Coffee maker



1935- J. 'r. H. DEMPSTER 2,011,397

COFFEE MAKER Filed April 14, 1934 2 Sheets-Sheet l Invent or JohnI HDem Sher,

is ALLo1' ne5.

3, 1935. J. -r. H. DEMPSTER 2,011,397

COFFEE MAKER Filed April 14, 1934 2 Sheets-Sheet 2 if if Inventow John T H Deng steP Hts. .ALtonne u is somewhat chilled by contacting the walls of I Patented Aug. 13, 1935 2,011,397

UNITED STATES PATENT OFFICE In!!! men Jog-n: g. lie-pater M21: 1., as-

tien of New In Application All! ll, 1. let-l NO. 720,.

I M. (OI. 21H.)

'I'hisinvention relatestocoifeemakeramore pairofeiectrodesarrangedtodenneam particularlytocofleemakeraofthefl'renchdrip betweenthemthroughwhichthewaterironthe type,andithasforitsoblecttheprovisionofan upnereontainer'passestctbesrmindcoileeedaimproved device of this character t Coii'eemakersofthedriptype generallycombercomnletesaneieciriccircuitb'etwedithe 5 priseagroundcofleecontainerandameeptacle electrodesandishnted'bythepassage v for receiving hot water arranged over it and tric current through it. Preferably, the elsehaving an imperforate bottom wall through which trodes will be arranged luh h m thewaterflows at arelativelyslowratetoand lr i'theheatinschambemonebeinglflllll d iothroughthecoii'eecontainertoformthecoiiee abovetheotherandthetwo in my being spaced infusion or brew. Beneath the cute container r l ion to defin he h in lD ehlmher is areeeptacle for receiving the coifee brew, between than. liach electrode is provided with Itisdesirableinmakingcoifeeinthistypeof apluralityofsubstantiallyverticallyarranged apparatus that the water delivered to the coil'ee conduits. those in the upper electrode conducting 1g groundsfromtheupperreceptaclebeheldata ote irom e mreocntscletothehsat substantiallyconstanttemperatiirewithinthe inesvaoeandthossintheiowsreiectrodsconrange of approximately 192 to 198' I This has duetihl helted r t0 the been very diillcult and practically impossible to container. 'IhUe latter also function to m do with most of the coffee makers heretofore li e he h eted Vi W th Hillier whee 0! generally used, because the water is heated by the eelee n l-ih l' 20 separate means, such as a gas or an electric fsrshlath h tins ehlmber'fllheflmned range, and is then poured into the upper water as a unit separate from the other elements of receptacle. The temperature of the water placed e maker o a it ca b c ve ently removed within the receptacle is reduced first because it or tta h d. as d s d. It is pr ferable to arrange the heating element so that it can be seatthe receptacle which usually are comparatively ed in the upper Portion of the r w r e iiteele cool, and then since it requires from flvetoten end eleeeothlt it l reeeive It iuin r nd minutes for the water to seep through the ground the Voter p M r p cifi lly. it i coil'ee to the brew receptacle, there is a considpreferable to arrange the lower container with erable loss of temperature by radiation. The e eeet f r r v ns h h lm hI-m r nd 30 first part only, therefore, of the water reaching likewise to provide a seat in the heating element the ground coflee is likely to have a temperature lving the upper receptaclewithin the desired range. The remainder is usu- For a more omp ete understanding of this inally entirelytoo cooltomake good coii'ee. vention, reference should be had to the accomgi This invention contemplates the provision of D nying drawings in whi h F t 1 is an levation an improved coflee maker arranged to continuof a ooflee mak r dv s this nv n n, parts ally heat the water gravitatlng m w w t being shown in section and parts being broken receptacle as it pages to the go away so as to illustrate certain details of conthat every bit or the water that rea h th struction; Fig. 2 is a horizontal sectional view 49 grounds will be heated substantially to the detaken through the line 1-2 of Pi 1 and look- 40 sired uniform tem eratur ing in the direction of the arrows: and Pig. 8

It is a further object ofthis invention to prois a pers c view o a p o o e conevide suitable heating means which is automatifetus sh wn in Pi cally turned on when water is poured into the ef rring to the drawings. hi invention has upper receptacle andis automaticalLv tiu'ned oil been Shown in One form as pplied to a coffee 45 when all of the water in the receptacle has dripped mike! 01 the French drip im comprising a cofthrough the coffee grounds. fee ground container II, a waterreceptaele II A still further object of his invention is the arranged abov the I lm e flee container and provision of an improved heating element for arranged to permit water placed therein to ravu drip coilee makers. itate or drip to the coffee container, and a lower In accordance with this invention in one form receptacle I; arranged below the coifee conthereof a suitable heating chamber is arranged tainer to receive the codes infusion or brew made between the ground coifee container and the upby the seepage or percolation of water through per container for receiving the fresh water. the ground coifee in the container II. The rell Withinthe heating chamber are provided a ceptacles ii and I! are provided with handles 66 Na and |2a respectively. The receptacle H is provided with a cover llb.

Preferably, the ground coifee container l0 will be supported within and from the upper edges of the side walls of the container |2. As shown, the coffee container I0 is secured to a member |3 that is fitted within the upper end of the infusion receptacle l2. The member I3 is provided with a vertical cylindrical.wall H which is arranged within the walls 01' the receptacle I2 and having a sliding fit therein. This portion I4 is provided with a bead II at its upper edge for limiting the insertion of themember I3. The member l3, as shown, is also provided with another cylindrical vertical portion l6 whch has a diameter somewhat less than the diameter of the portion l4 and the walls of the container i2. The coffee container I6 is secured to this portion M5 by bayonet connections (only one being shown).

The container "I is provided with an imperforate" bottom wall |8 through which the water percolatin. through the ground coffee in the contain r can flow to the infusion reception I2.

The upper or water receptacle likewise is provided with an imperforate bottom wall l9 through which the water is delivered to the coffee container l0.

Interposed between the coffee container l0 and the upper water receptacle is a heating chamber 26 arranged to heat the water gravitating from the upper receptacle I to the coffee container |0 so that all of the water that reaches the coffee container has substantially the same desired temperature. I

The heating chamber 26 s provided with a pair of electrodes 2| and 22 arranged transversely of the chamber, as clearly shown in Fig. 1. These electrodes may be formed of any suitable material, but preferably will be formed of graphite or carbon, or a mixture of these materials, because they are resistant to wear, and moreover, graphite or a mixture of graphite and carbon having a large percentage of graphite avoids the depos t of injurious products, such as lime or other salt deposits, as might be occasioned if the electrodes were formed of metal.

The electrodes 2| and 22, as shown, are substantially circular in shape, that is, they have a substantial disc shape, and they are arranged with n the heating chamber one above the other so as to define a relatively narrow heating chamber 23 between them. The electrodes preferably will be supported by a ring-like member 24 which in turn is supported within an outer frame or casing 25. Each electrode 2| and 22 is supported by a plurality of spherical members 26 which, as shown, are provided with seats 21 in the supporting ring 24 corresponding to the balls; and with -a. seat 28 in the electrode. Whereas the seats 23 in the electrodes are formed continuously about the peripheries of the electrodes, as shown in Fig.

2, separate seats 21 for each ball are formed at.

spaced intervals in the supporting ring 24 for the purpose of holding the spheres 26 in spaced relation with each other circumferentially of the ring and the electrodes. The ring 24 and spheres 26 may be assembled with the electrodes by making the member 24 as a split ring that may be sprung apart to receive the electrodes and the spheres, after which the split ends may be secured by any suitable connection, such as a tongue and slot connection 30.

The spheres 26 are formed of any suitable electrically insulating material, such as porcelain, so

as to effectively insulate the electrodes from the ring 24.

The electrodes 2| and 22 are secured in their vertically spaced relation with respect to each other to define the chamber 23 by means of a plurality of spheres 3|, likewise formed of an electrically insulating material, such as porcelain. As shown (Fig. 2), three of these spheres 3| are provided spaced substantially apart. The electrodes 2| and 22 are provided with seats 32 and 33 respectively (Fig. 1) for receiving these balls.

Suitable electrical terminals 34 and 35 respectively are electrically and mechanically connected with the electrodes 2| and 22. As shown, each of these terminals is secured by a threaded con nection to its electrode. These members 34 and 36 are electrically connected with suitable terminal pins 36 of a plug and socket supply connec tfon well-known in the art.

' The supporting ring 24 is supported at its side opposite the terminals by means of a suitable screw 31, which, as shown, is directed through an aperture provided for it in the casing 25 and is received in screw-threaded relation by the ring 24. A suitable spring washer 38 is positioned between the two rings so as to space the ring 24 from the casing 25. The terminal side of the ring 24 is secured to the casing 25 by means of the terminals 34 and 35.

The upper electrode 2| is provided with a plurality of vertically arranged passageways 40 passing through the electrode so as to provide conduits through which the water dripping from the container II can pass to the transverse passageway or chamber 23 between the electrodes. The lower electrode 22 is provided with similarly arranged conduits 4| establishing communication between the chamber 23 and the ground coffee container I0. Preferably, the passageways 40 at their upper ends will communicate with circular channels 43, as clearly shown in Fig. 2, and preferably the upper ends of the conduits 4| in the lower electrode will communicate with similarly arranged channels 44. It is also preferable to arrange the conduits 4| in the lower electrode in staggered relation with respect to the conduits 46 in the upper electrode, as shown in Fig. 2, whereby the water flowing to the narrow chamber 23 from the upper electrode will be spread laterally in different directions to form a thin film or sheet of water between the electrodes before it can gravitate through the conduits 4| to the coffee container. It will be observed that the conduits 4| in the lower electrode distribute the water substantially uniformly over the coffee container ID.

The lower end of the frame or casing 26 rests in a seat 45 provided for it in the member 3, while its upper end is provided with a seat 46 for receiving the lower end of the water receptacle II, as shown clearly in Fig. 1.

Suitable means are provided for locking the receptacles H and I2 and the heating chamber 20 together. This means comprises vertically arranged arms 41 and 43 arranged above and below the terminal receptacle, as shown in Fig. l. Pins 53 project laterally from the sides of these members, as shown in Figs. 1 and 3. The pin 50 on the upper arm 41 is received in a suitable recess 6| provided for it in the handle ||a of the upper container, while the pin 66 of the lower arm 43 is received within a similar recess provided for it in the handle |2a of the lower container. when the heating chamber 20 has been assembled with the lower receptacle I2 and the upper receptacle H has been assembled with the heating chamber, as shown in Pig. 1, the can be turned relatively to each bring the pins I. within their recesses II. This looks the members together so as to prevent displacement or tipping of the members from each other when the coffee is poured from the lower receptacle It.

In the operation of this apparatus, if it is desired to make coifee. the upper receptacle ii and the heating chamber" will be removed from the lower receptacle. and the desired amount of ground coflee will be placed within the container it. Then the heating chamber and the upper receptacle will be replaced, and the desired quantity of water placed within the upper container H.

Previous to this, the terminal pins 80 will have been plugged into a suitable source of electrical supply. As soon as the water is placed within the receptacle Ii, it begins to gravitate through its bottom perforated wall II to the upper surface of the upper electrode II. The water finds its way to the circular channels 48 and then fiows down through the vertical conduits 40 to the chamber 23. As soon as the water reaches the chamber 23, it spreads out in a thin film between the two electrodes and completes an electric circuit between them whereby the water is heated substantially to the boiling point. The heated water in this chamber finds its way to the circular channels 44 in the upper surface of the lower electrode and from these nnels'fiows down through the conduits I to e coffee container ill through which the water percolates or seeps into the brew receptacle II. The water continues to flow through the electrode chamber 23 in this manner so as to be heated until all of the water has drained but of the receptacle ll into the coffee container ll, whereupon the electric circuit between the two electrodes II and" is automatically broken. This automatically turns off the heat.

-It will be observed, therefore, that the electric heater is automatically turned on when water is placed within the receptacle II and is automatically turned oil when the coffee has been made.

The electrodes 2| and 21, as shown, are made relatively thick so that they have a relatively large heat storage capacity. These electrodes become heated very quickly and apply heat to the water in the chamber Ii above it. Thus, the water is heated not only by completing an electric circuit between the two electrodes, but also is preheated to a rather high temperature by conduction of heat from the electrodes to the body of water in the container II.

It has been found that while the water within the chamber 28 has substantially the boiling temperature of 312 F., the water which falls into the coffee container I. will have a temperature between 192" to 198 F. and that this temperature will remain substantially constant. That is, all of the water delivered to the coffee container II has substantially the same temperature falling within this range. This is quite important because it has been found'by actual experiment that far better coffee is made when the temperature is thus held constant than when the water temperature gradually cools as in the case of drip coffee makers heretofore generally used.

It is preferable to lock the receptacles I i and I! in the manner previously described so that it is unnecessary'to'disassemble the, parts after the coffee has been made. Thus, the coffee can be poured from the container it without danger of the upper receptacle ll toppling over. However, if desired, after thecoifeehasbeen made the upper receptacle II, the heating chamber fl and likewise the coffee container II can be removed if desired before the coffee is poured.

. An important feature of this invention resid in the fact that the electrical heating element II is turned on and off automatically when water is poured into the receptacle II and when the codes has been made. Thus, there is no possibility that the heating element can burn out by reason of the fact that the attendant has left the cofi'ee maker plugged into the electrical supply scurce.

Another important feature of this invention resides in the fact that the wattage input to the coffee maker drops considerably while the water is being heated. Thus, whereas the current consumption at the very beginning of the operatitn rises rapidly to approximately 500 watts, it quickly drops oil! to around 300 watts and then gradually drops off to zero as the quantity of water in the receptacle ll decreases. This is because the electrodes become heated, as previously described, and in turn transfer heat to the water remaining in the vessel II.

It is contemplated that the heating unit 2| comprising the electrodes 2| and if, their supporting ring 24 and the frame 2', together with the plug receptacle, will be formed as a separate unit which may be applied to existing French drip coffee makers now being used. It will be observed that the frame I! is arranged to be inserted within the seat H which normally is provided for the upper receptacle II, and at its upper end is provided with a seat 46 which receives the lower end of the receptacle ii that normally is placed within the seat ll of the lower receptacle.

As previously pointed out, the electrodes are formed of graphite or a mixture of this material and carbon. This is important because it has been found that the electrodes shed" or throwof! lime and other salts that may be deposited on them. This is probably dueto the greasy or slippery nature of graphite.

While I have shown a particular embodiment of my inventiion, it will be understood, of course, that I do not wish to be limited thereto since many modifications may be made, and I, therefore, contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is,-

l. A coffee maker and the like comprising a coffee infusion receptacle, a ground coffee cont ainer in the upper portion of said receptacle, a heating imit above said coffee container comprising a pair of electrodes arranged transversely of said coffee container and in vertically spaced relation with each other so as to define a relatively narrow chamber between them transversely of said cofi'ee container, a water receptacle above said heating unit having means whereby water therein can flow to the upper surface of the upper of said electrodes, said upper electrode having a plurality of vertically arranged passageways for. conducting said water on said upper surface to said chamber between said electrodes, and the lower of said electrodes having a plurality of vertically arranged passageways for conducting the water from said chamber to and distributing it over said coffee container.

2. A coffee maker and the like comprising a coffee infusion receptacle, a separable ground coffee container having a portion seated within the upper end of said receptacle and provided with a bead at its upper end engaging the upper end of said receptacle to support said container, said portion being provided with a circular supporting portion, a separable heating chamber having its lower end seated on said supporting portion and having at its upper end a circular supporting portion, and a separable water receptacle having its lower end seated on said circular supporting portion of said heating chamber.

3. A coffee maker and the like comprising a coffee infusion receptacle, a perforate ground coffee container in the upper portion of said receptacle, a water receptacle above said coffee container having an imperforate bottom wall, a heating chamber between said water chamber and said coffee container, a pair of electrodes within said heating chamber formed chiefly of graphite arranged transversely thereof one above the other in spaced relation so as to define a relatively narrow chamber between them, each of said electrodes having a plurality of vertically arranged conduits establishing communication between said narrow chamber and said water receptacle and said coffee container respectively, the conduits in each electrode being in staggered relation with those in the other electrode and those of said lower electrode functioning to distribute the heated water over the coffee grounds in said coffee container, means for electrically insulating said electrodes from each other and from the walls of said heating chamber, and electrical supply terminals connected to said electrodes.

4. A heating unit for a coffee maker of the French drip type comprising a frame adapted to be seated in the lower infusion receptacle of said maker and adapted to receive in its upper end the upper water receptacle of said maker, electrical heating means in said frame arranged to heat the water while it drops from said upper to said lower receptacle and terminal pins for said heating means carried by said frame accessible on the exterior thereof for the reception of an electrical supply plug.

5. A heating unit for a coffee maker of the French drip type comprising a frame adapted to be seated in the lower infusion receptacle of said maker and adapted to receive in its upper end the upper water receptacle of said maker, and a pair of electrodes formed chiefly of graphite in said frame defining a chamber for receiving the water from said upper receptacle and heating said water while it flows through said chamber by passing an electrical current through it.

6. A heating unit for a coffee maker of the French drip" type comprising a frame adapted to be seated in the lower infusion receptacle of said maker and adapted to receive in its upper end the upper water receptacle of said maker, a pair of electrodes having substantially the same surface area arranged cross wise of said frame one above the other, insulating members interposed between said electrodes holding them in vertically spaced relation, insulating members interposed between each of said electrodes and said frame arranged to support said electrodes in said frame, terminal pins carried by said frame on the exterior thereof, and electrical connections between said terminal pins and said electrodes.

7. A heating unit for a coffee maker of the.

French drip type comprising a frame adapted to be seated in the lower infusion receptacle of said maker and adapted to receive in its upper end the upper water receptacle of said maker, a pair of electrodes, a plurality of spherical insulating members between said electrodes received in recesses provided for them in said electrodes and arranged to hold said electrodes in spaced relation to define a water passageway between them, a plurality of spherical insulating members between each of said electrodes and said frame received in recesses provided for them in said electrodes and frame and arranged to secure said electrodes to said frame, terminal pins carried by said frame on the exterior thereof and electrical comiections between said terminal pins and said electrodes.

JOHN T. H. DEMPS'I'ER. 

